1. Field of the Invention
The present invention relates to a turbocharger which includes a turbine and a compressor.
2. Description of the Related Art
A turbocharger including a turbine and a compressor has been widely used as a supercharger for improving a performance of an internal combustion engine. In the turbocharger, a turbine wheel (turbine impeller) constituting the turbine and a compressor wheel (compressor impeller) constituting the compressor are connected to each other by a rotating shaft. An exhaust gas from the internal combustion engine is fed into the turbine side. The exhaust gas thus fed rotates the turbine wheel and thereby rotates the compressor wheel. Air is forced to flow into a cylinder of the internal combustion engine by the rotation of the compressor wheel, whereby a gas pressure inside the cylinder is raised and virtual displacement is increased.
The above-described turbocharger needs to rotate and drive the turbine and the compressor at a high speed. As a consequence, the rotating shaft is also rotated at a high speed. It is therefore extremely important to ensure lubrication between the rotating shaft and a housing that houses the rotating shaft. Japanese Patent Application Laid-Open Publication No. 2010-96120 (PTL 1) cited below proposes a bearing device for a turbocharger, which is intended to remove foreign matter in oil that serves as a lubricant.
In the bearing device of PTL 1, a detour is provided in the vicinity of an oil inlet inside a housing and a filter is disposed in the detour. Foreign matter in the oil is removed by the filter, and the oil from which the foreign matter is removed is then supplied from the inlet to rolling bearings.